Angle-calculator.



W.N. R'IAZOM1n.-A AANGLE C'ALQULATCR. v APPLICATION FILED rss. 2. lara. f

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WILL N. REZOR, 323)., 0F' ELMIRA, NEW YORK.

ANGLE-CALCULATOR.

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Specification of Letters Patent.

Patented May 3, 112919.

Application filed February 2, 1913. Serial No. 215,063.

provide a device of this class which will be adapted for the solution of problems relating to the various forms of triangles met with in engineering and shop work, and be accurate, easily operable and comparatively simple and inexpensive.

Other objects and the features of novelty will be apparent from the following description taken in connection with the accompanying drawings of which,

Figure 1 is a p an view of a device em.- bodying the invention;

Fig. 2 is a section on Fig. 3 is a plan view of a removable scale used in the solution of certain kinds of triangles; l Figs. 4 and 5 are triangles, the solution of by my invention, is hereinafter described.

Reierring to the drawings, 10 indicates a board or base for the other parts of the device. A base scale 11 is fixed on the base 10, and a parallel scale 12 is preferably arranged at the opposite side of base 10. A bar 13 is slidably arran ed on scales 11 and 12 at right angles` t ereto. rll`he bar 13 is preferably provided, at its ends, with vermers 14 and 15 to coperate with the scales 11 and 12,'respectively. A xed pivot 16 is provided adjacent the zero marl; on scale 11 and a plate 17 is arranged to turn on this pivot. rlhe bar 13 carries a pivot 18 so placed that its line of movement extends -through the pivot 16 or, in other words, the pivots 16 and 19 are arranged with their axes equidistant from the'base scale 11.- A scale arm 19 is secured to the plate d17 and carries a runner 20 having a vernierto coperatewith the scale on arm 19. The edge 21 of the runner 20 is in alinement with the axis of pivot 16,.'and an index or hairline 22 on the runner at this edge.` A protractcr -23 is provided on the base 10, about the pivot 16,-and the end of the `scale i:

line 2-2 of Fig. 1;

is provided has a Vernier 24 for, coperation with this protractoi.

A scale larm 25 is arranged on the pivot 13 and moves with 'the bar 13 relatively to the base scales 11 and 12. 'llhe bar 13 carries a protractor 26 which is arranged about the pivot 18 and an arm 27 extending from the arm 25 has a Vernier 28 arranged to cooperate With the protractor 26 to indicate the angular relation ofthescale arm 25 to the base scale 11.

The plate 17 has 'a slot 29 extending across 'its upper surface and at right angles to the scale arm 19. The slot 29 is adapted to receive the end 30 of the detachable scale arm 31, which is preferably marked in the same manner as scale arm 19.

A runner 33 is provided on the scale arm 25, the edge 34 of the runner alining with the pivot 18, and an index or hairline 35 is arranged on this edge. `The runner 33 is also provided with a Vernier 36 adapted to cooperate with the scale on arm 25. A thumb nut 37 is provided on the pivot 18 to clamp the scale bar 25 in any position to which it may be set.

The operation of the device is as follows: The scale bar 31 is ordinarily omitted as it is not necessary for solving problems relating to more common forms of triangles. 1n Fig. 5, there is illustrated a common form of triangle, all of the sides of which are of known dimensions, the included angles, however, bein unknown. In the solution of this triangle, t e bar 13 is shifted so that its indexes will register with the numbers 17.9.7` on scales 11 and 12, the verniers 14 and 15 being employed to accurately position the bar 13. The scale 11 then represents the side b of the triangle. The runner 20 is then adjusted to the value 13.83 on the scale arm 19, this arm then representing the side a of the triangle. rlhe runner 33 is adjusted on scale arm 25 to the ,value 21.69 so that this scale arm will represent the side o of the triangle. r1`he scale arms 19 and 25 are then swung on their respective pivots until edges of the runners 20 and 33 coincide at the indexes 22 and 35. rlhe'angle between the sides a and be readily formed by subtracting the sum of' the other two angles from 180.

To solve the triangle shown in Fig. 4, the

scale arm 31 is secured in position on the fixed pivot, two right angularly arranged plate 17 as shown in broken lines in Fig. 1 scale arms' movable on said fixed pivot, a pro- The bar 13 is then set at 6.8 on scales 11 and tractor in fixed relation with said base scale 30 12 so that scale 11 will represent the side b and cooperating with one of said scale arms of the triangle. The scale arm 25 is then to measure the angle between the latter and swung on the pivot 18 until the Vernier 28 the base scale, a scale arm arranged to swing indicates 20o-17 on the protractor 26. The on said movable pivot, and means for measrunner 33 is thus adjusted on the scale arm uring the angular relation of the last-men- 35 to the value 10.2 of the side c of the tritioned scale arm and said base scale.

10 angle. The scale arms 19 and 31 and the run- 2. In a device of the class described, the ner 20, which in this case will be placed von combination of a base scale, a fixed pivot, a scale arm 31, are adjusted until the edges of pivot movable in a line parallel with said y the runners 20 and 33 coincide at the indexes base scale and which extends through said 40 22 and 35. The angle between the sides a fixed pivot, two right angularly arranged 15 and b may then be read, obtained by adding scale arms movable on said fixed pivot, a O to the indication on the protractor 23, protractor in fixed relation with said base and the value of the side a may be read from scale and cooperating with one of said scale the scale arm 31. The value of the angle bearms to measure the angle between the latter 45 tween the sides a and b may then be ascerand the base scale, a scale arm arranged to 2o tained by subtracting the sum of the other swing on said movable pivot, a protractor two angles from movable with said movable pivot, and means Having described the, invention what is on the last-mentioned scale arm adapted to claimed is: coperate with the last-mentioned protractor 5o 1. In a device of the class described, the for measuring the angular relation of this 25 combination of a base scale, a fixed pivot, a scale arm and said base scale.

pivot movable in a line parallel with said In testimony whereof I afiix my signature. base scale and which extends through said WILLIAM N. REAZOR, JR. 

